Pseudomonas putida oxidizes toluene to cis-toluene dihydrodiol. The enzyme system catalyzing this reaction has been resolved into three protein components. The current project involves the purfication and properties of each component. These are ferredoxinTOL reductase which transfers electrons from NADH to ferredoxinTOL (The latter is a plant-type ferredoxin that is essential for enzymatic activity); FerredoxinTOL which is a 2FE-2S protein that is currently being sequenced and toluene dioxygenase a non-heme iron sulfur protein. Pseudomas putida NP oxidizes naphthalene to cis-naphtalene dihydrodiol. The enzyme system has been resolved into three components each of which will be purified and characterized. The purified enzyme systems will be used to investigate the mechanisms of enzymatic dioxygen fixation.